Remove new lines in the new & diff values of the update content

src/job.rs

@@ -179,14 +179,10 @@ impl Job {
             .guid(Some(guid))
             .content(format!(r#"
 New content at {}: <br>
-<pre class="new-value">
+<pre class="new-value">{}</pre>
-{}
-</pre>
 <br><br>
 Diff: <br>
-<pre class="diff-value">
+<pre class="diff-value">{}</pre>
-{}
-</pre>
 "#,
                              update_time.format("%d/%m/%Y %H:%M"),
                              value,